The present invention relates generally to the field of ultralight unit load devices such as air cargo pallets and in particular to a ruggedized quadrangular composite structure with a cellular load-bearing core sealed in successive ordered-polymer stiffening plies and trimmed at the outer edges with a hollow, multi-chambered profile of lightweight material fixed with flush head rivets so as to present a flat surface for easy loading and unloading of payloads.
The loading of air freight within the cargo compartment of an aircraft typically involves the use of pallets, available in a variety of different sizes, which are disposed in the aircraft and are otherwise designed to support and retain cargo thereon. A primary benefit to the use of such pallets is the ability to load a large volume of smaller items at one time, after they have been pre-loaded on the pallet at a remote location. Moreover, the pallet functions to maintain the items securely and uniformly retained on the aircraft. In particular, the supported load is typically maintained in its intended position on the pallet by means of some type of retaining cover or structure, specifically designed to allow the maximum load to be placed on each pallet, while at the same time assuring that the loaded cargo will not shift or be inadvertently displaced from the pallet during take-offs, landings or during the actual in-flight maneuvers of the aircraft.
Current air cargo pallets are composed of solid sheets of high strength, lightweight metals such as aluminum sheets typically weighing in the range of 96 to 138 kg or greater for at least an 88×125 inch dimension, depending on configuration and material and teach a base sheet thickness of 0.2 inches or less. See, for instance, the air cargo pallets sold as product nos. 081203 and 081244 by Alcan Singen GmbH, as product no. 463L by MR mobility systems, and U.S. Pat. No. 6,308,642 to Branam et al. (“Pallet Assembly”) and U.S. Pat. No. 5,284,098 to Klapperich et al. (“Air Cargo Pallet”). As weight is a principle concern in the aviation industry, any advancement in the design of such pallets that can reduce the overall weight while maintaining load-bearing capacity and structural integrity would be welcomed.
The light-metal base plate of an air cargo pallet cannot insure heavy-load carrying capability by itself without being prone to deformation. Therefore, such pallets are typically filted with light-metal hollow profile edges primarily designed to have an enhancing effect on the load-carrying capability of the pallet by allowing for flexible and elastic deformation in response to impact, alternating and continuous loads and related strain.
The light-metal hollow profiles also have another function due to their flat outer edges. Many air and land transport vehicles and storage facilities are equipped with holding systems designed to receive air cargo pallets along their flat outer edges. In this way, the pallets are prevented from tilting during inclined positions, accelerations or decelerations. Typically, these hollow profiles are also constructed with upwardly open T-shaped longitudinal slots designed to accept mushroom or plunger shaped heads for securing payload by means of stretching nets and the like. These T-shaped slots are well known in the prior art and are typically designed so that the narrowed portions at the edge of the slots used to retain said mushroom or plunger heads are raised in elevation above the plane of the light-metal hollow profile. Examples of this design can be found at FIG. 3 of U.S. Pat. No. 5,284,098 to Klapperich et al. (“Air Cargo Pallet”) and FIGS. 5 and 6 of U.S. Pat. No. 6,308,642 to Branam et al. (“Pallet Assembly”). The raised profile of these constructions prohibit the free sliding movement of payloads, increasing the amount of time it takes to load and unload cargo and, commensurately, the costs of transport.
Along the bottom, inner margins of above said light-metal hollow profiles is usually a step-like shoulder into which the light-metal plate is inserted so that at the bottom it is flush with the light-metal hollow profile and riveted together. This construction is designed to counteract the shear strain acting at the level of the light-metal plate. Reference again is made to FIG. 3 of U.S. Pat. No. 5,284,098 to Klapperich et al. (“Air Cargo Pallet”) and FIGS. 5 and 6 of U.S. Pat. No. 6,308,642 to Branam et al. (“Pallet Assembly”) and the air cargo pallets sold as product nos. 081203 and 081244 by Alcan Singen GmbH. As in the instance of the slots mentioned above, the raised profile of this shoulder construction prohibits the free sliding movement of payloads, increasing the amount of time it takes to load and unload cargo and the commensurate costs. There is a long-felt need in the aviation industry for a solution that will reduce the logistical costs and complexities of payload movement without sacrificing the payload capacity and structural integrity of air cargo pallets.
The rigors of air transportation demand a highly durable pallet construction that is resistant to deformation to prevent the shifting of weight during flight and can withstand an abusive regimen of loading and unloading of payload under severe time constraints and in less than ideal conditions. There is, therefore, a long-felt need in the aviation industry for the construction of low maintenance, safe, ruggedized pallets.
Pallets such as those sold by Alcan Singen GmbH as product nos. 801237 and 801238 are heavy, deformable and have an elevated edge.
Therefore, a need exists for a durable, lightweight, unit loading device with a flat profile that meets aviation industry specifications such as that set forth in National Aerospace Standard (NAS) 3610.